(A) Field of the Invention
This invention is generally in the field of differentiating between malignant and benign tumors of the gastric mucosa and specifically in the field of gastric cancer diagnosis as a tool in early and reproducible detection of gastric cancer by assaying the gastric juice of the patient.
(B) Description of the Prior Art
It is generally accepted among immunologists that tumors may be regarded as invasive grafts of tissue which should evoke homograft reactions in so far as they possess antigens foreign to their hosts. Thus, tumors are subject to principles governing immunological tolerance (see Humphrey and White, Immunology for Students of Medicine, 3rd Edition 1970, 2nd printing 1971, Blackwell Publications, page 580).
It is also accepted that antigens have been detected in human carcinomas of the gastrointestinal tract which are absent from the corresponding normal tissue of their hosts but are present in embryonic tissues of the same species. These antigens represent the product of genes which are normally repressed in adult cells (see "Immunology . . . " as cited above, page 583). These last named antigens are presumed to represent products of genes which are normally repressed in adult cells and are distinctly different from virus induced tumors or tumors elicited by chemical carcinogens.
The invention has found and reported with his coworkers in Cancer Research, volume 33, January 1973, that an antigen which is different from and distinct from Gold's carcinoembryonic antigen is present in gastric cancer secretions and reacts immunochemically to give one precipitin line on double diffusion in agar gel.